Parkinson Disease Panel

Updated
Summary
  • Is a 62 gene panel that includes assessment of non-coding variants.
  • In addition, it also includes the maternally inherited mitochondrial genome. Is ideal for patients with a clinical suspicion of Parkinson disease.

Analysis methods
  • PLUS
Availability

4 weeks

Number of genes

62

Test code

NE1501

Panel size

Large

CPT code *
81443(1)
* The CPT codes provided are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payer being billed.

Summary

The Blueprint Genetics Parkinson Disease Panel (test code NE1501):

Test Specific Strength

It can detect the VPS35 c.1858G>A, p.(Asp620Asn) variant, which is within the pseudogene region and is known to be challenging to detect by NGS technologies.

ICD codes

Commonly used ICD-10 code(s) when ordering the Parkinson Disease Panel

ICD-10 Disease
F84.2 Rett syndrome
H49.40 Progressive external ophthalmoplegia
G20 Parkinson disease
G11.9 Hereditary ataxia
C94.2 Acute Megakaryoblastic Leukemia
K59.8 Chronic Intestinal Pseudoobstruction
T36.5 Adverse effect of aminoglycosides
G93.41 Metabolic Encephalopathy
H49.81 Kearns Sayre Syndrome
E88.42 MERFF Syndrome
H47.013 Nonarteritic Anterior Ischemic Optic Neuropathy
G60.2 Neuropathy in association with hereditary ataxia
G30 Alzheimer's Disease
G25.5 Chorea
G40 Epilepsy and recurrent seizures
I42 Cardiomyopathy
N26.9 Focal Segmental Glomerulosclerosis
G31.82 Leigh's Disease
H47.2 Leber's hereditary optic neuropathy
G71.3 Mitochondrial Myopathy
I42.1 Hypertrophic Cardiomyopathy
E11.9 Non-Insulin Dependent Diabetes Mellitus
Z86.74 Personal history of sudden cardiac arrest
H90.3 Sensorineural Hearing Loss

Sample Requirements

  • Blood (min. 1ml) in an EDTA tube
  • Extracted DNA, min. 2 μg in TE buffer or equivalent
  • Saliva (Please see Sample Requirements for accepted saliva kits)

Label the sample tube with your patient's name, date of birth and the date of sample collection.

We do not accept DNA samples isolated from formalin-fixed paraffin-embedded (FFPE) tissue. In addition, if the patient is affected with a hematological malignancy, DNA extracted from a non-hematological source (e.g. skin fibroblasts) is strongly recommended.

Please note that, in rare cases, mitochondrial genome (mtDNA) variants may not be detectable in blood or saliva in which case DNA extracted from post-mitotic tissue such as skeletal muscle may be a better option.

Read more about our sample requirements here.

Parkinson disease is the second most common neurodegenerative disorder, after Alzheimer disease. Its diagnosis is based on the clinical findings of tremor, rigidity, and bradykinesia. Psychiatric manifestations, which include depression and visual hallucinations, are common but not uniformly present. Dementia eventually occurs in at least 20% of cases. Mendelian (monogenic) forms of Parkinson disease are found in fewer than 5% of all patients and are inherited in an autosomal dominant, autosomal recessive, or, very rarely, X-linked manner. Mendelian forms of Parkinson disease have an earlier age of disease onset than families with typical, late-onset Parkinson disease. Non-Mendelian Parkinson disease is thought to result from the effects of multiple genes as well as environmental risk factors.

Genes in the Parkinson Disease Panel and their clinical significance

Gene Associated phenotypes Inheritance ClinVar HGMD
ATP13A2 Parkinson disease (Kufor-Rakeb syndrome) AR 21 40
ATP1A3 Alternating hemiplegia of childhood, Dystonia 12 AD 79 112
DNAJC6 Juvenile Parkinsonism AR 5 14
FBXO7 Parkinson disease AR 5 15
GCH1 Dopa-Responsive Dystonia Hyperphenylalaninemia, BH4-deficient, GTP Cyclohydrolase 1-Deficient Dopa-Responsive Dystonia AD/AR 48 240
LRRK2 Dementia, Lewy body, Parkinson disease AD 14 123
MAPT Pick disease, Frontotemporal dementia, Parkinson-dementia syndrome, Supranuclear palsy, progressive AD/AR 26 104
MT-ATP6 Neuropathy, ataxia, and retinitis pigmentosa, Leber hereditary optic neuropathy, Ataxia and polyneuropathy, adult-onset, Cardiomyopathy, infantile hypertrophic, Leigh syndrome, Striatonigral degeneration, infantile, mitochondrial Mitochondrial 19
MT-ATP8 Cardiomyopathy, apical hypertrophic, and neuropathy, Cardiomyopathy, infantile hypertrophic Mitochondrial 4
MT-CO1 Myoglobinuria, recurrent, Leber hereditary optic neuropathy, Sideroblastic anemia, Cytochrome C oxidase deficiency Mitochondrial 17
MT-CO2 Cytochrome c oxidase deficiency Mitochondrial 8
MT-CO3 Cytochrome c oxidase deficiency, Leber hereditary optic neuropathy Mitochondrial 9
MT-CYB Mitochondrial 69
MT-ND1 Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes, Leber hereditary optic neuropathy, Leber optic atrophy and dystonia Mitochondrial 21
MT-ND2 Leber hereditary optic neuropathy, Mitochondrial complex I deficiency Mitochondrial 6
MT-ND3 Leber optic atrophy and dystonia, Mitochondrial complex I deficiency Mitochondrial 7
MT-ND4 Leber hereditary optic neuropathy, Leber optic atrophy and dystonia, Mitochondrial complex I deficiency Mitochondrial 11
MT-ND4L Leber hereditary optic neuropathy Mitochondrial 2
MT-ND5 Myoclonic epilepsy with ragged red fibers, Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes, Leber hereditary optic neuropathy, Mitochondrial complex I deficiency Mitochondrial 19
MT-ND6 Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes, Oncocytoma, Leber hereditary optic neuropathy, Leber optic atrophy and dystonia, Mitochondrial complex I deficiency Mitochondrial 16
MT-RNR1 Deafness, mitochondrial Mitochondrial 3
MT-RNR2 Chloramphenicol toxicity/resistance Mitochondrial 2
MT-TA Mitochondrial 4
MT-TC Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes Mitochondrial 3
MT-TD Mitochondrial 1
MT-TE Diabetes-deafness syndrome, Mitochondrial myopathy, infantile, transient, Mitochondrial myopathy with diabetes Mitochondrial 5
MT-TF Myoclonic epilepsy with ragged red fibers, Nephropathy, tubulointerstitial, Encephalopathy, mitochondrial, Epilepsy, mitochondrial, Myopathy, mitochondrial, Mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes Mitochondrial 7
MT-TG Mitochondrial 3
MT-TH Mitochondrial 4
MT-TI Mitochondrial 7
MT-TK Mitochondrial 5
MT-TL1 Cytochrome c oxidase deficiency, Myoclonic epilepsy with ragged red fibers, Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes, Diabetes-deafness syndrome, Cyclic vomiting syndrome, SIDS, susceptibility to Mitochondrial 14
MT-TL2 Mitochondrial multisystemic disorder, Progressive external ophthalmoplegia Mitochondrial 5
MT-TM Leigh syndrome, Mitochondrial multisystemic disorder Mitochondrial 1
MT-TN Progressive external ophthalmoplegia, Mitochondrial multisystemic disorder Mitochondrial 3
MT-TP Mitochondrial 2
MT-TQ Mitochondrial multisystemic disorder Mitochondrial 2
MT-TR Encephalopathy, mitochondrial Mitochondrial 2
MT-TS1 Myoclonic epilepsy with ragged red fibers, Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes Mitochondrial 10
MT-TS2 Mitochondrial multisystemic disorder Mitochondrial 2
MT-TT Mitochondrial 5
MT-TV Hypertrophic cardiomyopathy (HCM), Leigh syndrome, Mitochondrial multisystemic disorder Mitochondrial 3
MT-TW Leigh syndrome, Myopathy, mitochondrial Mitochondrial 8
MT-TY Mitochondrial multisystemic disorder Mitochondrial 4
PARK2 Parkinson disease, juvenile AR 45 432
PARK7 Parkinson disease, early onset AR 10 35
PDGFB Basal ganglia calcification, idiopathic, 5 AD 8 19
PDGFRB Basal ganglia calcification, idiopathic, 4, Kosaki overgrowth syndrome, Premature aging syndrome, Penttinen type AD 14 19
PINK1 Parkinson disease, early onset AR 17 136
PLA2G6 Parkinson disease, Neurodegeneration with brain iron accumulation AR 78 175
PRKRA Dystonia 16 AR 2 9
SLC20A2 Basal ganglia calcification, idiopathic, 1 AD 22 71
SLC39A14# Hypermanganesemia with dystonia 2 AD/AR 9 9
SLC6A3 Parkinsonism-dystonia, infantile AR 8 31
SNCA Parkinson disease, Dementia with Lewy bodies AD 7 35
SPR Dystonia, Dopa-responsive, due to sepiapterin reductase deficiency AR 12 23
SYNJ1 Epileptic encephalopathy, early infantile, 53, Parkinson disease 20, early-onset AR 12 25
TH Segawa syndrome, autosomal recessive AR 44 71
VPS13A Choreoacanthocytosis AR 19 115
VPS13C Parkinson disease 23, autosomal recessive, early onset AR 10 9
VPS35* Parkinson disease AD 2 22
XPR1 Basal ganglia calcification, idiopathic, 6 AD 4 6

* Some, or all, of the gene is duplicated in the genome. Read more.

# The gene has suboptimal coverage (means <90% of the gene’s target nucleotides are covered at >20x with mapping quality score (MQ>20) reads), and/or the gene has exons listed under Test limitations section that are not included in the panel as they are not sufficiently covered with high quality sequence reads.

The sensitivity to detect variants may be limited in genes marked with an asterisk (*) or number sign (#)

Gene refers to the HGNC approved gene symbol; Inheritance refers to inheritance patterns such as autosomal dominant (AD), autosomal recessive (AR), mitochondrial (mi), X-linked (XL), X-linked dominant (XLD) and X-linked recessive (XLR); ClinVar refers to the number of variants in the gene classified as pathogenic or likely pathogenic in this database (ClinVar); HGMD refers to the number of variants with possible disease association in the gene listed in Human Gene Mutation Database (HGMD). The list of associated, gene specific phenotypes are generated from CGD or Mitomap databases.

Non-coding variants covered by Parkinson Disease Panel

Gene Genomic location HG19 HGVS RefSeq RS-number
GCH1 Chr14:55369403 c.-22C>T NM_000161.2
MAPT Chr17:44087661 c.1774-15T>C NM_016835.4
MAPT Chr17:44087779 c.1866+11T>C NM_016835.4 rs63751394
MAPT Chr17:44087780 c.1866+12C>T NM_016835.4 rs63750916
MAPT Chr17:44087781 c.1866+13A>G NM_016835.4 rs63750308
MAPT Chr17:44087782 c.1866+14C>T NM_016835.4 rs63750972
MAPT Chr17:44087783 c.1866+15A>C NM_016835.4
MAPT Chr17:44087784 c.1866+16C>T NM_016835.4 rs63751011
MAPT Chr17:44087787 c.1866+19C>G NM_016835.4 rs63750162
PARK2 Chr6:163148721 c.-21G>T NM_004562.2
PARK7 Chr1:8021919 c.-24+66C>G NM_007262.4
SLC20A2 Chr8:42328683 c.289+937G>A NM_006749.4
SNCA Chr4:90647315 c.*464C>A NM_000345.3 rs183204610
SPR Chr2:73114549 c.-13G>A NM_003124.4 rs750423023
TH Chr11:2187017 c.1198-24T>A NM_199292.2
TH Chr11:2188749 c.738-34G>C NM_199292.2
TH Chr11:2193085 c.-69T>A NM_199292.2
TH Chr11:2193086 c.-70G>A NM_199292.2
TH Chr11:2193087 c.-71C>T NM_199292.2 rs549435434

Added and removed genes from the panel

Genes added Genes removed
MT-ATP6
MT-ATP8
MT-CO1
MT-CO2
MT-CO3
MT-CYB
MT-ND1
MT-ND2
MT-ND3
MT-ND4
MT-ND4L
MT-ND5
MT-ND6
MT-RNR1
MT-RNR2
MT-TA
MT-TC
MT-TD
MT-TE
MT-TF
MT-TG
MT-TH
MT-TI
MT-TK
MT-TL1
MT-TL2
MT-TM
MT-TN
MT-TP
MT-TQ
MT-TR
MT-TS1
MT-TS2
MT-TT
MT-TV
MT-TW
MT-TY

Test Strengths

It can detect the VPS35 c.1858G>A, p.(Asp620Asn) variant, which is within the pseudogene region and is known to be challenging to detect by NGS technologies.

The strengths of this test include:
  • CAP accredited laboratory
  • CLIA-certified personnel performing clinical testing in a CLIA-certified laboratory
  • Powerful sequencing technologies, advanced target enrichment methods and precision bioinformatics pipelines ensure superior analytical performance
  • Careful construction of clinically effective and scientifically justified gene panels
  • Some of the panels include the whole mitochondrial genome (please see the Panel Content section)
  • Our Nucleus online portal providing transparent and easy access to quality and performance data at the patient level
  • Our publicly available analytic validation demonstrating complete details of test performance
  • ~2,000 non-coding disease causing variants in our clinical grade NGS assay for panels (please see ‘Non-coding disease causing variants covered by this panel’ in the Panel Content section)
  • Our rigorous variant classification scheme
  • Our systematic clinical interpretation workflow using proprietary software enabling accurate and traceable processing of NGS data
  • Our comprehensive clinical statements

Test Limitations

The following exons are not included in the panel as they are not sufficiently covered with high quality sequence reads: SLC39A14 (NM_001135154:9). Genes with suboptimal coverage in our assay are marked with number sign (#) and genes with partial, or whole gene, segmental duplications in the human genome are marked with an asterisk (*) if they overlap with the UCSC pseudogene regions. Gene is considered to have suboptimal coverage when >90% of the gene’s target nucleotides are not covered at >20x with mapping quality score (MQ>20) reads. The technology may have limited sensitivity to detect variants in genes marked with these symbols (please see the Panel content table above).

This test does not detect the following:
  • Complex inversions
  • Gene conversions
  • Balanced translocations
  • Some of the panels include the whole mitochondrial genome but not all (please see the Panel Content section)
  • Repeat expansion disorders unless specifically mentioned
  • Non-coding variants deeper than ±20 base pairs from exon-intron boundary unless otherwise indicated (please see above Panel Content / non-coding variants covered by the panel).
This test may not reliably detect the following:
  • Low level mosaicism in nuclear genes (variant with a minor allele fraction of 14.6% is detected with 90% probability)
  • Stretches of mononucleotide repeats
  • Low level heteroplasmy in mtDNA (>90% are detected at 5% level)
  • Indels larger than 50bp
  • Single exon deletions or duplications
  • Variants within pseudogene regions/duplicated segments
  • Some disease causing variants present in mtDNA are not detectable from blood, thus post-mitotic tissue such as skeletal muscle may be required for establishing molecular diagnosis.

The sensitivity of this test may be reduced if DNA is extracted by a laboratory other than Blueprint Genetics.

For additional information, please refer to the Test performance section and see our Analytic Validation.

The genes on the panel have been carefully selected based on scientific literature, mutation databases and our experience.

Our panels are sectioned from our high-quality, clinical grade NGS assay. Please see our sequencing and detection performance table for details regarding our ability to detect different types of alterations (Table).

Assays have been validated for various sample types including EDTA-blood, isolated DNA (excluding from formalin fixed paraffin embedded tissue), saliva and dry blood spots (filter cards). These sample types were selected in order to maximize the likelihood for high-quality DNA yield. The diagnostic yield varies depending on the assay used, referring healthcare professional, hospital and country. Plus analysis increases the likelihood of finding a genetic diagnosis for your patient, as large deletions and duplications cannot be detected using sequence analysis alone. Blueprint Genetics’ Plus Analysis is a combination of both sequencing and deletion/duplication (copy number variant (CNV)) analysis.

Performance of Blueprint Genetics high-quality, clinical grade NGS sequencing assay for panels.

Sensitivity % (TP/(TP+FN) Specificity %
Single nucleotide variants 99.89% (99,153/99,266) >99.9999%
Insertions, deletions and indels by sequence analysis
1-10 bps 99.2% (7,745/7,806) >99.9999%
11-50 bps 99.13% (2,524/2,546) >99.9999%
Copy number variants (exon level dels/dups)
1 exon level deletion (heterozygous) 100% (20/20) NA
1 exon level deletion (homozygous) 100% (5/5) NA
1 exon level deletion (het or homo) 100% (25/25) NA
2-7 exon level deletion (het or homo) 100% (44/44) NA
1-9 exon level duplication (het or homo) 75% (6/8) NA
Simulated CNV detection
5 exons level deletion/duplication 98.7% 100.00%
Microdeletion/-duplication sdrs (large CNVs, n=37))
Size range (0.1-47 Mb) 100% (25/25)
     
The performance presented above reached by Blueprint Genetics high-quality, clinical grade NGS sequencing assay with the following coverage metrics
     
Mean sequencing depth 143X
Nucleotides with >20x sequencing coverage (%) 99.86%


Performance of Blueprint Genetics Mitochondrial Sequencing Assay.

Sensitivity % Specificity %
ANALYTIC VALIDATION (NA samples; n=4)
Single nucleotide variants
Heteroplasmic (45-100%) 100.0% (50/50) 100.0%
Heteroplasmic (35-45%) 100.0% (87/87) 100.0%
Heteroplasmic (25-35%) 100.0% (73/73) 100.0%
Heteroplasmic (15-25%) 100.0% (77/77) 100.0%
Heteroplasmic (10-15%) 100.0% (74/74) 100.0%
Heteroplasmic (5-10%) 100.0% (3/3) 100.0%
Heteroplasmic (<5%) 50.0% (2/4) 100.0%
CLINICAL VALIDATION (n=76 samples)
All types
Single nucleotide variants n=2026 SNVs
Heteroplasmic (45-100%) 100.0% (1940/1940) 100.0%
Heteroplasmic (35-45%) 100.0% (4/4) 100.0%
Heteroplasmic (25-35%) 100.0% (3/3) 100.0%
Heteroplasmic (15-25%) 100.0% (3/3) 100.0%
Heteroplasmic (10-15%) 100.0% (9/9) 100.0%
Heteroplasmic (5-10%) 92.3% (12/13) 99.98%
Heteroplasmic (<5%) 88.9% (48/54) 99.93%
Insertions and deletions by sequence analysis n=40 indels
Heteroplasmic (45-100%) 1-10bp 100.0% (32/32) 100.0%
Heteroplasmic (5-45%) 1-10bp 100.0% (3/3) 100.0%
Heteroplasmic (<5%) 1-10bp 100.0% (5/5) 99,997%
SIMULATION DATA /(mitomap mutations)
Insertions, and deletions 1-24 bps by sequence analysis; n=17
Homoplasmic (100%) 1-24bp 100.0% (17/17) 99.98%
Heteroplasmic (50%) 100.0% (17/17) 99.99%
Heteroplasmic (25%) 100.0% (17/17) 100.0%
Heteroplasmic (20%) 100.0% (17/17) 100.0%
Heteroplasmic (15%) 100.0% (17/17) 100.0%
Heteroplasmic (10%) 94.1% (16/17) 100.0%
Heteroplasmic (5%) 94.1% (16/17) 100.0%
Copy number variants (separate artifical mutations; n=1500)
Homoplasmic (100%) 500 bp, 1kb, 5 kb 100.0% 100.0%
Heteroplasmic (50%) 500 bp, 1kb, 5 kb 100.0% 100.0%
Heteroplasmic (30%) 500 bp, 1kb, 5 kb 100.0% 100.0%
Heteroplasmic (20%) 500 bp, 1kb, 5 kb 99.7% 100.0%
Heteroplasmic (10%) 500 bp, 1kb, 5 kb 99.0% 100.0%
The performance presented above reached by following coverage metrics at assay level (n=66)
Mean of medians Median of medians
Mean sequencing depth MQ0 (clinical) 18224X 17366X
Nucleotides with >1000x MQ0 sequencing coverage (%) (clinical) 100%
rho zero cell line (=no mtDNA), mean sequencing depth 12X

Bioinformatics

The target region for each gene includes coding exons and ±20 base pairs from the exon-intron boundary. In addition, the panel includes non-coding and regulatory variants if listed above (Non-coding variants covered by the panel). Some regions of the gene(s) may be removed from the panel if specifically mentioned in the ‘Test limitations” section above. If the test includes the mitochondrial genome the target region gene list contains the mitochondrial genes. The sequencing data generated in our laboratory is analyzed with our proprietary data analysis and annotation pipeline, integrating state-of-the art algorithms and industry-standard software solutions. Incorporation of rigorous quality control steps throughout the workflow of the pipeline ensures the consistency, validity and accuracy of results. Our pipeline is streamlined to maximize sensitivity without sacrificing specificity. We have incorporated a number of reference population databases and mutation databases including, but not limited, to 1000 Genomes Project, gnomAD, ClinVar and HGMD into our clinical interpretation software to make the process effective and efficient. For missense variants, in silico variant prediction tools such as  SIFT, PolyPhen, MutationTaster are used to assist with variant classification. Through our online ordering and statement reporting system, Nucleus, ordering providers have access to the details of the analysis, including patient specific sequencing metrics, a gene level coverage plot and a list of regions with suboptimal coverage (<20X for nuclear genes and <1000X for mtDNA) if applicable. This reflects our mission to build fully transparent diagnostics where ordering providers can easily visualize the crucial details of the analysis process.

Clinical interpretation

We provide customers with the most comprehensive clinical report available on the market. Clinical interpretation requires a fundamental understanding of clinical genetics and genetic principles. At Blueprint Genetics, our PhD molecular geneticists, medical geneticists and clinical consultants prepare the clinical statement together by evaluating the identified variants in the context of the phenotypic information provided in the requisition form. Our goal is to provide clinically meaningful statements that are understandable for all medical professionals regardless of whether they have formal training in genetics.

Variant classification is the corner stone of clinical interpretation and resulting patient management decisions. Our classifications follow the ACMG guideline 2015.

The final step in the analysis is orthogonal confirmation. Sequence and copy number variants classified as pathogenic, likely pathogenic and variants of uncertain significance (VUS) are confirmed using bi-directional Sanger sequencing by orthogonal methods such as qPCR/ddPCR when they do not meet our stringent NGS quality metrics for a true positive call.

Our clinical statement includes tables for sequencing and copy number variants that include basic variant information (genomic coordinates, HGVS nomenclature, zygosity, allele frequencies, in silico predictions, OMIM phenotypes and classification of the variant). In addition, the statement includes detailed descriptions of the variant, gene and phenotype(s) including the role of the specific gene in human disease, the mutation profile, information about the gene’s variation in population cohorts and detailed information about related phenotypes. We also provide links to the references, abstracts and variant databases used to help ordering providers further evaluate the reported findings if desired. The conclusion summarizes all of the existing information and provides our rationale for the classification of the variant.

Identification of pathogenic or likely pathogenic variants in dominant disorders or their combinations in different alleles in recessive disorders are considered molecular confirmation of the clinical diagnosis. In these cases, family member testing can be used for risk stratification. We do not recommend using variants of uncertain significance (VUS) for family member risk stratification or patient management. Genetic counseling is recommended.

Our interpretation team analyzes millions of variants from thousands of individuals with rare diseases. Our internal database and our understanding of variants and related phenotypes increases with every case analyzed. Our laboratory is therefore well-positioned to re-classify previously reported variants as new information becomes available. If a variant previously reported by Blueprint Genetics is re-classified, our laboratory will issue a follow-up statement to the original ordering health care provider at no additional cost.

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